Add Linux DTS files for 32 bit threaded FVPs

RevC models have the MT bit set and the affinities shifted in the MPIDR
register. To make the Linux able to boot all CPUs it needs a modified
DTS file containing the shifted affinity values.

Beside these values the DTS files should be the same so the common part
was moved into a new file which is included in the DTS files with
shifted and non-shifted affinities.

The same setup already exists for 64 bit systems.

Signed-off-by: Imre Kis <imre.kis@arm.com>
Change-Id: I90f7b9c8d8a24c9b3f97232441dbe0a29aa8976d